Valve gear for internal-combustion engines



Patented May l, 1928.

`UNETED STATES `PATENT OFFICE.

THOMAS 'lOIllrflNIEYS' MOILRAITH, OF COLCHESTER, ENG-LAND.

VALVE GEAR FOR NTERNAL-COMBUSTION ENGINES.

Application ined August 31, i927,

This invention relates to mechanism for operatingthe valves of internal combustion engines, and it has for its object the actuation of the valve in a manner which provides advantages not found in existing mechanisms.

l attain this end by the construction shown in the aecompanying` drawing in which z-liigure l is a broken view in side elevation, and Figure 2 is a broken view in plan.

ln both views similar parts are` marked with like numerals of reference.

On to the spindle l ol: the valve-which in the accompanying drawing is shown of the poppet type but which may be of any other type having a direct lifting action-is iixed a tappet 2 which slides in a bonnet guide 3 carried by the valve box 4 or any other convenient part of the engine. The tappet Q is forked to carry a roller 5 which is mounted on a. pin (i carried by said fork and its forked ends 7, 7 are extended to give to the tappet a maximum of bearing surface. The bonnet guide 3` is also provided with two longitudinal slots 8 and 8 with which the fork of the tappetregisters.

ln advance of the guide 3 and in parallel relation to the pin 6 is a transverse shaft 9 on which is mounted the operating cam 10 which may be either oi the reciprocating type formed on and operated by a lever l1 through a link 12 as shown in the accompanying drawing, or it may be of the rotating type. rl`his cam engages the roller 6 and through the tappet 2 imparts the necessary motion to litt the valve against the action oit springs 13 which operates to close it. These springs are conveniently arranged one on each side of the guide 3 and act between transverse extensions 14C of the pin G and lined anchors l5 carried by the end ot the said `guide.

rlhe shape of the cam l() is such that the radius of its entrant end 1G is slightly less than the distance between the axis of the shaft Sl and. that part of the :am s iriface adjacent to its acting or lifting surface 17, and the radius of the curvature of said acting or lifting surface is slightly greater than halt the diameter of the roller 5.

Beneath the Ouide 3 is a box-like receptacle 18 which Iorms an oil bath into which the cam l0 dips at each reciprocation or i revolution through the slot 8 in the lower Serial No.. 216,705, and in Great Britain February 28, 1927.

part ot' the guide as shown in dot and dash lines in Figure l and so operates to carry oil to the roller 5 the pin 5, the tappet 2 and its guide 8.

What I claim is l. ln a valve operating mechanism for internal combustion engines the combination with the valve, ol a. forked tappet carried by the stem of the valve, a fixed guide adapted to receive said tappet, slots in said guide with which the fork of the tappet registers, a transverse 'pin mounted in the `forked part of the tappet, a roller mounted on said pin,

springs'operating between extensions of said i transverse pin and lined points on the guide, s

ot its entrant part is slightly less than the distance between the axis o'l' the shaft carrying the cam and that part or' the cam surtace adgacent to its lifting surface and that the radius ol the curvature of said cam surtace is slightly greater than half the diameter of' the roller carried by the tappet.

2. In a valve operating mechanism for internal combustion engines the combina tion with the valve, of a tappet mounted on the stem of the valve' which is slotted at its forward end, a iixed guide adapted to receive said tappet slots in said guide with which the fork of the tappet registers, a transverse pin mounted in the forked part of the tappet, a roller mounted on said pin, springs operating between extensions of said transverse pin andlixed points on the guide,

transverse shaft mounted in bearingslocated in advance of said guide, a cam mountedon said shai't and adapted to engage the roller carried by the tappet, the shape of the cam being such that the adius ot'. its entrant part slightly less than the dis` tance between the axis ot the shaft carrying the cam and that part of the cum surface adjacent to its lifting surface and that the radius ot the curvature of said cam surface is slightly greater than half the diameter ol the roller carried by the tappet, and an oil bath located below the guide of the tappet and in communication with said guide by the slot in its lower part.

THOMAS TOMNEY MGILRAITH.4

till 

